{"provider_url":"https://hatena.blog","title":"Monoid \u306e\u4f7f\u3044\u9053\u304c\u601d\u3044\u6d6e\u304b\u3073\u307e\u305b\u3093\u30fb\u30fb\u30fb","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fsirocco.hatenadiary.org%2Fentry%2F20130622%2F1371933686\" title=\"Monoid \u306e\u4f7f\u3044\u9053\u304c\u601d\u3044\u6d6e\u304b\u3073\u307e\u305b\u3093\u30fb\u30fb\u30fb - sirocco \u306e\u66f8\u3044\u3066\u3082\u3059\u3050\u306b\u5fd8\u308c\u308b\u30e1\u30e2\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","provider_name":"Hatena Blog","author_url":"https://blog.hatena.ne.jp/sirocco/","blog_title":"sirocco \u306e\u66f8\u3044\u3066\u3082\u3059\u3050\u306b\u5fd8\u308c\u308b\u30e1\u30e2","version":"1.0","type":"rich","published":"2013-06-22 05:41:26","description":"\u3068\u308a\u3042\u3048\u305a\u3001Nil \u3068 Cons \u306b\u3088\u308b\u30ea\u30b9\u30c8\u3067mempty\u3068mappend\u3092\u5b9a\u7fa9\u3057\u3066\u307f\u307e\u3057\u305f\u304c\u3001\u5143\u3005Haskell \u306e\u30ea\u30b9\u30c8\u306fMonoid\u306a\u306e\u3067\u610f\u5473\u304c\u3042\u308a\u307e\u305b\u3093\u3002 import Data.Monoid data List a = Nil | Cons a (List a) deriving(Show) instance Monoid (List a) where mempty = Nil mappend Nil Nil = Nil mappend a Nil = a mappend Nil a = a mappend (Cons a b) c = Cons a (mappend b c) l\u2026","author_name":"sirocco","width":"100%","categories":["Haskell"],"blog_url":"https://sirocco.hatenadiary.org/","height":"190","url":"https://sirocco.hatenadiary.org/entry/20130622/1371933686","image_url":null}